Wild winds mess with bird brains

Hur­ri­canes and global warm­ing are push­ing mi­gra­tory birds off course, and all kinds of un­usual species are find­ing their way to UK shores.

Element - - Global Bulletin - Guardian News & Me­dia 2011

Bri­tain’s avian im­mi­gra­tion fig­ures are set to soar to a record level this year. Bird­watch­ers say hur­ri­canes and se­vere weather in North Amer­ica and Asia have caused ma­jor dis­rup­tions to bird mi­gra­tions across the globe and swept an un­prece­dented num­ber of species to­wards the Bri­tish Isles.

Birds wing­ing their way to their breed­ing grounds on the other side of the At­lantic or in the Pa­cific have been left stranded in Bri­tain and Ire­land, adding their numbers to na­tive species.

Twitch­ers, as the most fa­nat­i­cal bird­watch­ing en­thu­si­asts are termed, have al­ready ob­served a to­tal of 442 species in the Bri­tish Isles this year. The high­est num­ber ever spot­ted in one year is 445, in 2008. “We only need three more and we will have equalled our record – I’m very con­fi­dent we are go­ing to see the record bro­ken be­fore the end of the year,” said Lee Evans, who runs the Bri­tish Bird­ing As­so­ci­a­tion.

Last month a Siberian rubythroat - a tiny brown bird with a scar­let chest - was spot­ted out­side Ler­wick in Shet­land. A na­tive of east Asia, it is ex­tremely rare in Bri­tain, but has now spent the past two weeks at the very north­ern edge of the na­tion, caught by the cam­eras of twitch­ers who have flocked to the is­land.

Sim­i­larly, a buf­fle­head - a small duck with a dis­tinc­tive bul­bous head - was spot­ted in a farm pond on the Lizard in Corn­wall. “It was ab­so­lutely knack­ered when it ar­rived,” said Evans. “It had been mi­grat­ing south from Canada to south­ern United States when it was swept out into the At­lantic by a storm. It had prob­a­bly trav­elled more than 3,000 miles, which ex­plains why it was knack­ered.” The buf­fle­head has since flown on, prob­a­bly to Por­tu­gal, he added.

Evans said that global warm­ing over the past decade was play­ing a key role in trans­form­ing bird move­ments across the globe. Cli­mate change was trans­form­ing weather pat­terns, caus­ing a dra­matic rise in hur­ri­canes and storms, par­tic­u­larly over the At­lantic.

“In the 1990s the av­er­age to­tal for numbers of bird species spot­ted ev­ery year was 412,” he added. “Now that fig­ure is around 440.

That is a very sig­nif­i­cant change and global warm­ing lies at the root of it.” In ad­di­tion, melt­ing Arctic sea ice may be in­volved. Or­nithol­o­gists have sug­gested that the dis­ap­pear­ance of ice cover is open­ing up mi­gra­tion routes over the north pole, mak­ing it eas­ier for birds from the Pa­cific to reach Bri­tain - such as the slaty-backed gull, a na­tive of the north Pa­cific, which ap­peared in the Thames es­tu­ary this year. A tufted puf­fin from the north Pa­cific, a medi­um­sized black seabird with dis­tinc­tive white fa­cial mark­ings, was re­cently seen in the UK, though only a hand­ful of spot­ters were in­volved and they only got a brief glimpse. The jump in bird species numbers in the Bri­tish Isles is good news for twitch­ers, who ob­ses­sively fol­low news of sight­ings in or­der to add rare species to their lists - though the in­crease does pose fi­nan­cial prob­lems for the bird­watch­ing com­mu­nity.

“It is an in­cred­i­bly ex­pen­sive hobby to keep up,” said Evans. “Most of the rare vis­i­tors ar­rive in the Scil­lies,the Outer He­brides, Orkney or Shet­land - all at the fringes of the Bri­tish Isles. Flights can cost GBP600 to get there.

“The al­ter­na­tive is to drive, then take the ferry. Ev­ery year I run up about 70,000 miles on my car do­ing this. That means spend­ing thou­sands of pounds just on petrol. Es­sen­tially, I go through a car a year to spot these birds. And now we are get­ting more and more of them.”

The Buf­fle­head duck has been pushed off its mi­gra­tory course

be­tween Canada and the US and wound up in the UK.

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